Intake apparatus

Abstract

An intake apparatus includes an intake apparatus body including a plurality of intake pipes and a distribution passage including a gas passage before branching which includes a first gas passage through which the external gas flows in a first gas flow direction and a second gas passage through which the external gas flows in a second gas flow direction, the second gas passage curving relative to the first gas passage at a downstream, and a gas passage after branching including a third gas passage branched in the first gas flow direction relative to the second gas passage and a fourth gas passage branched in an opposite direction from the first gas flow direction relative to the second gas passage, an angle formed between the second gas passage and the third gas passage is smaller than an angle formed between the second gas passage and the fourth gas passage.

The invention claimed is: 
     
       1. An intake apparatus comprising:
 an intake apparatus body including a plurality of intake pipes provided for respective cylinders of a multi-cylinder engine; and 
 a distribution passage distributing an external gas to the plurality of intake pipes, 
 the distribution passage including:
 a gas passage before branching including a first gas passage through which the external gas flows in a first gas flow direction and a second gas passage through which the external gas flows in a second gas flow direction, the second gas passage curving relative to the first gas passage at a downstream of the first gas passage; and 
 a gas passage after branching including a third gas passage branched in the first gas flow direction relative to the second gas passage and a fourth gas passage branched in an opposite direction from the first gas flow direction relative to the second gas passage, 
 
 an angle formed between the second gas passage and the third gas passage is smaller than an angle formed between the second gas passage and the fourth gas passage. 
 
     
     
       2. The intake apparatus according to  claim 1 , wherein the second gas passage is curved relative to the first gas passage so that an intersection angle between an extension line of the first gas passage and an extension line of the second gas passage forms an acute angle. 
     
     
       3. The intake apparatus according to  claim 1 , wherein a cross-sectional area of a cross-section orthogonal to the first gas flow direction at the first gas passage and a cross-sectional area of a cross-section orthogonal to the second gas flow direction at the second gas passage are constant. 
     
     
       4. The intake apparatus according to  claim 2 , wherein a cross-sectional area of a cross-section orthogonal to the first gas flow direction at the first gas passage and a cross-sectional area of a cross-section orthogonal to the second gas flow direction at the second gas passage are constant. 
     
     
       5. The intake apparatus according to  claim 1 , wherein each of the gas passage before branching and the gas passage after branching extends in a horizontal direction or extends while inclining downward from an upstream to a downstream in a state where the intake apparatus is mounted at a vehicle. 
     
     
       6. The intake apparatus according to  claim 2 , wherein each of the gas passage before branching and the gas passage after branching extends in a horizontal direction or extends while inclining downward from an upstream to a downstream in a state where the intake apparatus is mounted at a vehicle. 
     
     
       7. The intake apparatus according to  claim 3 , wherein each of the gas passage before branching and the gas passage after branching extends in a horizontal direction or extends while inclining downward from an upstream to a downstream in a state where the intake apparatus is mounted at a vehicle. 
     
     
       8. The intake apparatus according to  claim 1 , wherein the distribution passage configures a tubular member,
 a length of the second gas passage in an up-down direction in a state where the intake apparatus is mounted at a vehicle is greater than a sum of a thickness of the tubular member in the up-down direction at the first gas passage and a thickness of the tubular member in the up-down direction at the fourth gas passage. 
 
     
     
       9. The intake apparatus according to  claim 2 , wherein the distribution passage configures a tubular member,
 a length of the second gas passage in an up-down direction in a state where the intake apparatus is mounted at a vehicle is greater than a sum of a thickness of the tubular member in the up-down direction at the first gas passage and a thickness of the tubular member in the up-down direction at the fourth gas passage. 
 
     
     
       10. The intake apparatus according to  claim 3 , wherein the distribution passage configures a tubular member,
 a length of the second gas passage in an up-down direction in a state where the intake apparatus is mounted at a vehicle is greater than a sum of a thickness of the tubular member in the up-down direction at the first gas passage and a thickness of the tubular member in the up-down direction at the fourth gas passage. 
 
     
     
       11. The intake apparatus according to  claim 4 , wherein the distribution passage configures a tubular member,
 a length of the second gas passage in an up-down direction in a state where the intake apparatus is mounted at a vehicle is greater than a sum of a thickness of the tubular member in the up-down direction at the first gas passage and a thickness of the tubular member in the up-down direction at the fourth gas passage. 
 
     
     
       12. The intake apparatus according to  claim 1 , wherein the intake apparatus body and a distribution portion which constitutes the distribution passage are integrally provided with each other. 
     
     
       13. The intake apparatus according to  claim 2 , wherein the intake apparatus body and a distribution portion which constitutes the distribution passage are integrally provided with each other. 
     
     
       14. The intake apparatus according to  claim 1 , wherein the external gas includes at least one of exhaust gas which is recirculated and blow-by gas leaking at the multi-cylinder engine. 
     
     
       15. The intake apparatus according to  claim 2 , wherein the external gas includes at least one of exhaust gas which is recirculated and blow-by gas leaking at the multi-cylinder engine.